We would like to describe, with as much chemical detail as possible, the macromolecular interactions that govern the sequence of events in T4-infected Escherichia coli leading to the production of complete, infectious virus particles. In particular we are determining a) the requirements for (in terms of early viral gene function) and kinetic parameters of transcription and translation of representative late genes of T4 in vivo; b) the relationship between protein synthesis in vivo and the ability of isolated RNA to direct protein synthesis in vitro; and c) the role of individual components of the protein synthetic apparatus in the regulation of transcription and translation of viral genes.